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Guidelines for Managing Concussion in Sports: A Persistent Headache

Robert Roos


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In their approach to managing athletes who sustain concussions, sports physicians differ at least as widely as do the many published guidelines on the subject. The scarcity of scientific evidence makes practical decisions about when an athlete can safely return to the field difficult. Efforts to forge a consensus are underway, but controversy persists around such questions as whether a brief loss of consciousness should be classified as a severe concussion.

A rugby player is struck on the head by an opponent's knee as he is being tackled. He remains conscious, but he has confusion and amnesia that persist for 10 minutes. A neurologic exam is normal, and the player has no history of head injury. After the symptoms clear, do you let him go back into the game?

If you vote yes, you are outvoted—but not overwhelmingly. Thirty percent of the team physicians who responded to this survey question said they would let the player resume play the same day. Another 44% said they would keep him out for a week, and 21% said they would let him return the next day.

These findings come from survey responses (1) from 269 members of the American Medical Society for Sports Medicine, of whom two thirds worked as team physicians. Researcher E. James Swenson, Jr, MD, an associate professor in the Department of Orthopedics at the University of Rochester in New York, found similarly divided responses to many of the other case scenarios he presented in the survey.

The lack of physician consensus wasn't surprising, Swenson says, given the lack of consensus in the literature on concussion management in sports. Numerous sets of guidelines on the topic have been published, and they differ considerably in their classification of injuries and their criteria for letting an athlete return to play. Some list only three grades of concussion, while others include as many as six. Regarding signs and symptoms, some of the guidelines focus exclusively on confusion, amnesia, and loss of consciousness, but others mention dizziness, tinnitus, headache, and vertigo.

To sample the differences, compare the guidelines of Robert C. Cantu, MD (2), and those of the Colorado Medical Society (3) (table 1: Colorado Medical Society guidelines not shown)—the two sets perhaps best known to sports-minded physicians. Under the Colorado guidelines, an athlete who loses consciousness for 30 seconds because of a blow to the head would have a severe concussion and would be barred from play for a month. But under Cantu's guidelines, the athlete would have only a moderate concussion and could return in as little as a week if he or she had no other symptoms.

Table 1. Examples of Differing Concussion Classification Systems and Return-to-Play Recommendations

Guidelines of Robert C. Cantu, MD (2)

Return-to-Play Recommendations
Severity First

Grade 1 (mild): No loss of consciousness; posttraumatic amnesia less than 30 min May return to play if asymptomatic May return in 2 wk if asymptomatic at that time for 1 wk Terminate season; may return next year if asymptomatic
Grade 2 (moderate): Loss of consciousness less than 5 min or posttraumatic amnesia greater than 30 min Return after asymptomatic for 1 wk Wait at least 1 mo; may return then if asymptomatic for 1 wk; consider terminating season Terminate season; may return next year if asymptomatic
Grade 3 (severe): Loss of consciousness greater than 5 min or posttraumatic amnesia greater than 24 hr Wait at least 1 mo; may return then if asymptomatic for 1 wk Terminate season; may return next year if asymptomatic

Adapted from Cantu (2).

Guidelines of the Colorado Medical Society (3): not shown

Scant Scientific Evidence

A shortage of scientific evidence is the chief reason for the differences in guidelines. The impossibility of doing prospective, randomized human trials on concussion means the data on which to confidently base concussion management guidelines are scant. Experts agree on at least this much.

One textbook sums up the problem this way: "The major difficulty in the management of concussion has always been the lack of objective assessment of the degree of concussion and evidence of recovery (4)." In other words, there is no simple way to determine the seriousness of an injury or whether a player has fully recovered. Hence there are many differences in injury classification systems, which in turn lead to significant differences in return-to-play recommendations.

That an athlete who still has symptoms or signs of a concussion should not return to play is beyond question. But once the symptoms have cleared, how much longer should the player sit out? Different guidelines suggest waiting anywhere from 20 minutes to a week to a season to forever, depending on the grade of concussion and the patient's history.

"Anybody's estimate has just been purely guesswork," says Robert J. Johnson, MD, director of primary care sports medicine in the Department of Family Practice at Hennepin County Medical Center in Minneapolis and an editorial board member of The Physician and Sportsmedicine. Although concussion guidelines are often treated as if they're sacrosanct, he observes that they are actually fairly arbitrary.

"This is a mine field, fraught with a lot of controversy, opinion, and a considerable lack of consensus," says James C. Puffer, MD, football team physician and chief of the Division of Family Medicine at the University of California-Los Angeles Medical School and an editorial board member of The Physician and Sportsmedicine. "And I think it'll remain that way till we begin to get some good science to help us."

What's at Stake

The seriousness of the risks brings an urgency to the controversy. Even if an athlete never returns to contact sports, a single concussion can be life threatening. A closed head injury may involve intracranial hemorrhage, considered the leading direct cause of death in contact sports (5). And no physician wants to send a brain-injured player back into a game, where he or she would be vulnerable to a second head injury.

The biggest worry in returning an athlete to play is second-impact syndrome, a rapid, fatal brain swelling that may occur if a person suffers another head impact—even a minor one—before the symptoms of a previous concussion have fully cleared. Although it is rare, the deaths of several boxers, football players, and hockey players have been ascribed to second impact syndrome since it first was widely publicized in 1984 (6).

After recovery, the player's chance of suffering another concussion may be four times as high as that of a player who has never had a concussion (7). And repeated concussions could cause cumulative, permanent neurologic damage—like the "punch-drunk syndrome" seen in some boxers.

The scientific uncertainty surrounding these high-risk situations adds fuel to the debate. Why, for example, is second impact syndrome so rare? Some people may be less susceptible than others, but no one knows how to identify those at risk, according to Puffer.

Why are players who have suffered one concussion more prone to future concussions? It's unclear whether an individual athlete's playing style (for example, aggressive use of the head) leads to increased injury risk or whether the initial injury creates a physical predisposition for subsequent brain injury, Puffer says. Perhaps a combination of factors is involved.

And what's the risk of cumulative neurologic damage from concussions in sports other than boxing? The few football players who have had permanent brain damage from repeated concussions are exceptions, says Johnson, who works with several college football teams. He adds that applying evidence from boxing to football or hockey is questionable because professional boxers don't wear head protection and they deliberately attack their opponent's head. Some have concluded that "if you have repeated concussions, you're going to be mentally a basket case down the road," Johnson says. "But we haven't done long-term testing to find out if there is permanent deterioration."

A Try for Consensus

Despite these riddles, neurologist James P. Kelly, MD, is seeking to build broad support for a new set of concussion management guidelines. Kelly, formerly an assistant professor of neurology at the University of Colorado and now director of the Brain Injury Program at the Rehabilitation Institute of Chicago, was lead author of the 1991 Colorado guidelines (3). He has led an effort to revise those guidelines and win their acceptance by national neurology organizations.

"What Kelly has tried to do is get together the groups of individuals who have the greatest expertise in this area and come to some consensus that these are reasonable guidelines," says James E. Wilberger, MD, who is director of neurotrauma at Allegheny General Hospital in Pittsburgh and has done research (8) on head injuries in sports. The guidelines "have been done as well as they can be done, given the scientific limitations in trying to develop this particular type of guideline," he says.

As a result of Kelly's work, the revised Colorado guidelines have won endorsement from the executive board of the American Academy of Neurology (AAN). A summary of these revised guidelines is scheduled to be published as an AAN practice parameter this fall in Neurology, and a full-length article by Kelly is expected to be published shortly in JAMA, according to AAN staff member Theresa Schulz in Minneapolis. Kelly is also seeking endorsement from the American Association of Neurological Surgeons (AANS) and the Congress of Neurological Surgeons (CNS). Wilberger reports that the Joint Section on Neurotrauma and Critical Care of the AANS and CNS, which he chairs, has already approved the guidelines.

An Invitation to Litigation?

But some team physicians say there is little point in promoting new guidelines when scientific research is still lacking. According to Puffer, issuing another set of guidelines "serves really no purpose until we have better science. I think it'll just further confuse an already confused area."

Cantu concurs: "I don't want to come off as negative to people who are trying to get a consensus statement, but I personally think it's premature, based on the data." Cantu, whose own concussion guidelines are quoted—though not officially endorsed—by the American College of Sports Medicine, is chief of the Neurosurgery Service and director of the Service of Sports Medicine at Emerson Hospital in Concord, Massachusetts, and is an editorial board member of The Physician and Sportsmedicine.

But Kelly counters: "Where the scientific evidence is limited, you rely on the consensus of experts. If we had the scientific evidence, then consensus would be unnecessary."

Still, the existence of even a limited consensus, and especially medical society endorsement, represents a departure. Current guidelines (other than the Colorado guidelines) were published by individuals, not organizations, Cantu observes. He fears that medical society endorsement will tend to make the guidelines the de facto standard of care, rather than what he says they should be—"essentially a departure point for people to think about the problem."

He adds that if neurology associations endorse a set of recommendations, "then I'm afraid from a legal standpoint that you're putting a much stronger stamp of approval on it." Currently, if a physician gets sued for not following a certain concussion guideline, the defense can simply argue that he or she was following a different guideline, Cantu says.

But Kelly rejects the idea that AAN-approved guidelines will provide ammunition for patients seeking to sue their physicians over concussion management. "It's not a standard of care," he says of the new AAN document. "It certainly doesn't have that kind of scientific background. It's essentially a recommendation. If somebody strays from a recommendation like this, and they have good reasons for doing it, then they're clear. It's just like anything else in medicine."

Too Conservative?

That the Colorado guidelines—and most likely the forthcoming AAN guidelines—are conservative only adds to the concern that physicians who deviate from the guidelines will increase their vulnerability to malpractice litigation.

The Colorado guidelines are not used as widely as the Cantu guidelines, Swenson's survey of AMSSM members suggests. Physician choices in hypothetical clinical situations most nearly approximated the Cantu guidelines, and more respondents were familiar with Cantu's guidelines than with the Colorado guidelines, by 90% to 59%.

Swenson thinks that many team physicians, like himself, find the Colorado guidelines too restrictive. The main problem is the classification of even the briefest loss of consciousness as a grade 3 (severe) concussion that requires a hospital evaluation. "That's way too conservative," Swenson says, "and that's just not what's being done." He notes that 22% of the survey respondents would let an athlete who has a momentary blackout return to play the same day, barring other symptoms.

Cantu says he's much more concerned about an athlete who remains conscious but has 12 to 24 hours of posttraumatic amnesia than about an athlete who's out 30 seconds and is perfectly normal 5 minutes later. Cantu classifies the posttraumatic amnesia case as severe, whereas the Colorado system defines it as moderate.

Although the Colorado guidelines are endorsed by the National Collegiate Athletic Association (NCAA), Puffer says their recommendations—especially regarding waiting periods before return to play—are not pragmatic. "I make decisions every weekend which are contrary to the Colorado guidelines," he says. "From the standpoint of practicality, following them rigorously is very, very difficult to do in a large [NCAA] Division I football program. Or certainly at the professional level, they would simply be incredibly difficult to adhere to."

Johnson shares this view of the Colorado guidelines: "You're not going to do anyone harm by following them, because they're by far the most conservative, but on the other hand maybe we are limiting a person's play when it isn't necessary."

Shades of Difference

The AAN-endorsed guidelines are much the same as the Colorado guidelines, says Kelly, though they are slightly less conservative about return to play. In the new classification system, the difference between grade 1 and grade 2 concussions hinges on the duration of mental confusion rather than on the presence of amnesia; any loss of consciousness is still considered a grade 3 (severe) concussion. The revision recommends that an athlete who has a grade 3 concussion be kept out of play for a month, but says the player can return sooner if he or she has been asymptomatic for 2 weeks. The earlier Colorado guidelines say that players should not return to competition any sooner than a month after the injury, but they can resume conditioning sooner if they have been asymptomatic for 2 weeks.

Also in the new AAN version, an athlete who loses consciousness only momentarily and has no lingering symptoms can return to play in 1 week, according to Kelly. "We have never considered anything like that before," he says. "But that's what people are doing, and nowhere in the literature can we find a catastrophic outcome" from such action.

However, he insists that any loss of consciousness should still be classified as a severe concussion, because it indicates that both hemispheres of the brain or the brain stem has been directly affected. "And that's worrisome," he says. "Even if it is brief, it can evolve into a serious problem that we don't want to dismiss."

But Kelly also acknowledges the dilemma noted by Cantu: Some people who are rendered briefly unconscious recover quickly with no persisting symptoms, whereas others may suffer no loss of consciousness but have lingering symptoms. The AAN guidelines recognize this fact and suggest that the latter group are "more worrisome" than the former, Kelly says. The classification system is still the same, but the management suggestions acknowledge the problem of persisting symptoms without loss of consciousness, he says. "The issue becomes, 'Who do you send back into an at-risk activity?' and anybody who remains symptomatic simply doesn't go back."

Keeping Guidelines in Their Place

Whether physicians—and medical societies—will be able to reach a consensus about concussion guidelines is uncertain. But the team physician on the field can't wait. Puffer advises his fellows who are new to sports medicine to pick one set of guidelines and use them carefully for their first several years while they develop their own on-field decision-making skills. Just what guidelines they should choose remains open to debate.

Science Searches for Evidence to Guide Concussion Management

The scientific evidence available to back up concussion management decisions will always be limited. However, neuropsychological testing of athletes may offer physicians hope for a more scientific basis for their decisions.

By revealing persistent, subtle changes in an athlete who may otherwise feel well and appear normal, neuropsychological testing can "shed a lot of light on just how quickly these athletes ought to return to play, and for those with multiple concussions, how significant any deficits are and how long they last," says E. James Swenson, Jr, MD, who is an associate professor in the Department of Orthopedics at the University of Rochester in New York.

Unfortunately, most neuropsychological studies on athletes have been hampered by a lack of baseline data with which to compare current or postconcussion findings, observes James E. Wilberger, MD, director of neurotrauma at Allegheny General Hospital in Pittsburgh. Studies have tended to compare data on athletes with general-population norms, which may not be valid for athletes.

Wilberger's approach for the last several years has been to test high school students at the start of their football careers and then retest them each year and after any concussion. His aim is to detect changes over time or after an injury, as well as any differences between players who have had concussions and those who have not. No conclusive results are available yet.

Ideally, what's needed is a neuropsychological test that can be done in the office or even on the sidelines at a game. Such testing, however, can be expensive, says James P. Kelly, MD, director of the Brain Injury Program at the Rehabilitation Institute of Chicago, who points out that a 30-minute preseason test battery is needed to establish a baseline. While this is certainly within the price range of most college and professional teams, high school football teams may well require a different approach. A 30-point quantifiable mental status test that can be administered by a specially trained athletic trainer is another option that Kelly has been studying.


  1. Swenson EJ Jr, McKeag DB: Minor head injury evaluation: current state-of-the-art: results of survey completed by the AMSSM membership in 1994. Read before the annual meeting of the American Medical Society for Sports Medicine, Orlando, Florida, June 1996
  2. Cantu RC: Guidelines for return to contact sports after a cerebral concussion. Phys Sportsmed 1986;14(10):75-83
  3. Colorado Medical Society Sports Medicine Committee: Guidelines for the Management of Concussion in Sports. Denver, Colorado Medical Society, 1991
  4. Brukner P, Khan K: Clinical Sports Medicine. New York City, McGraw-Hill, 1993, p 157
  5. Schneider RC, Kennedy JC, Plant ML: Sports Injuries. Baltimore, Williams and Wilkins, 1985
  6. Saunders RL, Harbaugh RE: The second impact in catastrophic contact-sports head trauma. JAMA 1984;252(4):538-539
  7. Strich SJ: Shearing of nerve fibres as a cause of brain damage due to head injury: a pathological study of twenty cases. Lancet 1961;2:443-448
  8. Wilberger JE, Maroon JC: Head injuries in athletes. Clin Sports Med 1989;8(1):1-9

Robert Roos is senior editor of The Physician and Sportsmedicine.